Display device and method for manufacturing the same

Abstract

A display device includes a first substrate; a thin film transistor disposed on an upper surface of the first substrate; a plurality of pad electrodes disposed under a lower surface of the first substrate; a second substrate disposed under the lower surface of the first substrate and defining an opening therein exposing the plurality of pad electrodes; a circuit board attached onto the plurality of pad electrodes exposed through the opening of the second substrate; and a plurality of conductive ink patterns surrounding at least a side surface of the circuit board and being in contact with at least one of the plurality of pad electrodes, where lower surfaces of the plurality of conductive ink patterns each have a shape having a concave central portion.

What is claimed is: 
     
         1 . A display device comprising:
 a first substrate;   a thin film transistor disposed on an upper surface of the first substrate;   a plurality of pad electrodes disposed under a lower surface of the first substrate;   a second substrate disposed under the lower surface of the first substrate and defining an opening therein exposing the plurality of pad electrodes;   a circuit board attached onto the plurality of pad electrodes exposed through the opening of the second substrate; and   a plurality of conductive ink patterns surrounding at least a side surface of the circuit board and being in contact with at least one of the plurality of pad electrodes,   wherein lower surfaces of the plurality of conductive ink patterns each have a shape having a concave central portion.   
     
     
         2 . The display device of  claim 1 , wherein
 the circuit board includes a base and a bump disposed on the base, and   one end portion of the bump protrudes from one end portion of the base.   
     
     
         3 . The display device of  claim 2 ,
 wherein the plurality of conductive ink patterns cover at least a portion of the bump and the pad electrode, and electrically connect the bump and the pad electrode to each other.   
     
     
         4 . The display device of  claim 2 ,
 wherein the plurality of conductive ink patterns completely cover lower and side surfaces of the bump.   
     
     
         5 . The display device of  claim 2 , further comprising a non-conductive film disposed between the bump and the pad electrode. 
     
     
         6 . The display device of  claim 1 ,
 wherein a width of each of the lower surfaces of the plurality of conductive ink patterns is narrower than a width of each of upper surfaces of the plurality of conductive ink patterns.   
     
     
         7 . The display device of  claim 6 ,
 wherein side surfaces of the plurality of conductive ink patterns are inclined.   
     
     
         8 . The display device of  claim 1 , further comprising a barrier layer disposed between the first substrate and the second substrate,
 wherein the barrier layer exposes at least a portion of the pad electrode.   
     
     
         9 . The display device of  claim 1 , wherein
 a lower surface of each of the pad electrodes is hydrophilic, and   the lower surface of the first substrate adjacent to the pad electrode is hydrophobic.   
     
     
         10 . The display device of  claim 1 ,
 wherein the plurality of conductive ink patterns are adjacent to each other along a first direction and alternately disposed in a second direction different from the first direction.   
     
     
         11 . A method for manufacturing a display device, the method comprising:
 preparing a display panel and a circuit board; and   forming a plurality of conductive ink patterns under the display panel and the circuit board by seating a mask defining a plurality of holes therein and dropping conductive ink into the plurality of holes,   wherein the display panel includes:
 a first substrate; 
 a thin film transistor disposed on an upper surface of the first substrate; 
 a plurality of pad electrodes disposed under a lower surface of the first substrate; and 
 a second substrate disposed under the lower surface of the first substrate and defining an opening therein exposing the plurality of pad electrodes, 
   wherein the circuit board is attached onto the plurality of pad electrodes exposed through the opening of the second substrate,   the plurality of conductive ink patterns surround at least a side surface of the circuit board and is in contact with at least one of the plurality of pad electrodes, and   lower surfaces of the plurality of conductive ink patterns each have a shape having a concave central portion.   
     
     
         12 . The method of  claim 11 , wherein the forming of the conductive ink patterns includes:
 applying the conductive ink on the mask; and   pushing the conductive ink into the plurality of holes using a blade.   
     
     
         13 . The method of  claim 11 , wherein the forming of the conductive ink patterns includes:
 interposing a conductive ball in the plurality of holes; and   melting and dropping the conductive ball in a form of the conductive ink by irradiating the conductive ball with a laser.   
     
     
         14 . The method of  claim 11 , wherein
 the mask includes a first surface positioned on one side of the plurality of holes and a second surface positioned on an opposite side of the plurality of holes, and   a vertical length of the first surface is shorter than a vertical length of the second surface.   
     
     
         15 . The method of  claim 14 ,
 wherein a vertical-length difference between the vertical length of the first surface and the vertical length of the second surface is equal to a height difference between a lower surface of the circuit board and the lower surface of the first substrate.   
     
     
         16 . The method of  claim 11 ,
 wherein the plurality of holes are adjacent to each other along a first direction and alternately disposed in a second direction different from the first direction.   
     
     
         17 . The method of  claim 11 ,
 wherein each of the plurality of holes has a wider width in a direction from top to bottom thereof.   
     
     
         18 . The method of  claim 11 ,
 wherein a boundary of a bottom end portion of the mask coincides with a boundary of the opening.   
     
     
         19 . The method of  claim 11 ,
 wherein the conductive ink includes at least one of silver (Ag) nanoparticle ink, copper (Cu) nanoparticle ink, and metal organic decomposition ink.   
     
     
         20 . The method of  claim 19 ,
 wherein the conductive ink has a metal content of 50 weight percents (wt %) to 90 wt %.